Region: Northern Midcontinent|
State: all states
Anadarko Basin--Province SummaryThis description of the Anadarko Province is from the U. S. Geological Survey 1995 National Assessment of United States Oil and Gas Resources (available on CD-ROM from the U.S.G.S. as Digital Data Series DDS-30, Release 2).
The Anadarko Basin Province covers almost the entire western part of Oklahoma, the southwestern part of Kansas, the northeastern part of the Texas Panhandle, and the southeastern corner of Colorado. The province is bounded by major uplifts--the Wichita-Amarillo Uplift to the south, the Cimarron and Las Animas Arches to the west, the Central Kansas Uplift to the north, the Pratt Anticline to the northeast, the Nemaha Uplift to the east, and the Southern Oklahoma fold belt to the southeast. The Anadarko Basin is a large, deep, two-stage Paleozoic basin that is petroleum rich, and generally well explored (mature).
The province, as defined herein, includes an area of about 50,000 sq mi, and contains a thickness of sedimentary rocks that probably exceeds 40,000 ft in the deep southern part. Most strata range in age from Cambrian to Permian with some minor occurrences of Mesozoic and Cenozoic strata in the northwestern part of the province. Mississippian and older rocks are predominately carbonates, whereas Pennsylvanian and younger rocks are mostly shales with some sandstones. Although these sandstones comprise only a small part of the overall volume of basin rocks, they account for much of the petroleum production in the basins. The Morrowan sandstones, in particular, are major hydrocarbon producers. The number of sandstone reservoirs, relative to carbonate reservoirs, generally increases toward the deeper southern part of the basin. Carbonate-rock reservoirs are most common in the shallower northern shelf areas. Permian Council Grove and Chase Group carbonate-rock gas fields are by far the largest hydrocarbon producers in the basin.
Every Paleozoic system represented in the basin has produced some hydrocarbon. The province overall produces primarily gas. According to recent production data more than 2.3 BBO and more than 65.5 TCFG have been produced from the province since the early 1900's.
Stratigraphic trapping mechanisms are the most common, with combination types less common and structural types least common. Pennsylvanian and Permian rocks have produced the largest volumes of petroleum to date.
The Woodford Shale is considered to be one of the most important hydrocarbon source rocks in the province. It contains abundant organic matter, with both types II and III kerogens, and produces both oil and gas. It ranges from marginally mature (with respect to oil generation) in the shallow shelf areas to post mature in the deep basin. Ordovician and Pennsylvanian shales are also important source rocks and they too exhibit a wide range of thermal maturity levels from immature to post mature.
The surface area of the province has been drilled at least 200,000 times for an average of about 1 well for each 0.25 sq mi. This drilling density decreases significantly with depth. At the top of the Arbuckle, for example, drilling density is reduced to about 1 well for each 27 sq mi. Drilling density in the deep basin is even lower.
Twenty-five plays are identified in this province. Assigned to these plays are more than 1,100 known accumulations, each with a minimum expected ultimate recovery of 1 MMBO or 6 BCFG. Play boundaries generally coincide with province boundaries, except in areas where geologic conditions warrant. Where strata are absent, play boundaries are based on published maps or on the distribution of reported formation and (or) group tops. Quantitative, historical field-, reservoir-, and well-production data were heavily weighted in the assessment of undiscovered hydrocarbon resources of each play.
Twenty-four conventional plays were defined. A list of the plays follows:
Scientists affiliated with the American Association of Petroleum Geologists and from various State geological surveys contributed significantly to play concepts and definitions. Their contributions are gratefully acknowledged.
Kansas Geological Survey, Digital Petroleum Atlas
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Updated June 1996